International Conference on

“Refining Challenges & Way Forward”

April 16-17, 2012

Shangri-La's - Eros Hotel, 19 Ashoka Road,

New Delhi

Asha Masohan

INDIAN INSTITUTE OF PETROLEUM

Introduction

Regenerative process

Developmental studies @ IIP/EIL

Refinery applications:

A new paradigm

IIP on the frontier of acid gas treating

Introduction

Regenerative process

Developmental studies @ iip/eil

Refinery applications:

A new paradigm

IIP on the frontier of acid gas treating

Hazards of SO2 Emission

Gaseous SO2 : Highly toxic

◦ Adverse health effects

5-10 ppmv : Irritation of respiratory tract

400-500 ppmv: Dangerous to life

◦ Adverse environmental effects

Acid rains

Global SO2 emission by primary source

Global sweet sour crude production D

ail

y P

ro

du

cti

on

(M

BP

D)

Gradual Global Trend Towards Heavier and Higher Sulphur Crude

Sulfur production at petroleum refineries has increased at a faster rate than the refineries have increased input.

UNIT SO2 EMISSION, (Kg/day)

Crude distillation

#AU-1 419.28

#AU-2 418.8

#AU-3 238.8

#AU-4 1109.52

Vacuum distillation

#VDU 187.2

#FPU-1 537.84

FPU-2 622.08

Hydrocracking 732

Cat Reforming 131.28

Visbreaking 496.8

Sulphur recovery 1488

FCC 25.68

CO-Boiler 4725.6

TPS Utility block

#TPS 1849.68

#CGP 0

TOTAL 12982.56

Introduction

Regenerative process

Developmental studies @ iip/eil

Refinery applications:

A new paradigm

IIP on the frontier of acid gas treating

Advantages of Amine-based Regenerative FGD Technology

Regenerative process highly selective for SO2

Similar to conventional amine treating

Equipment/process design completely conventional

Absorbent: an aqueous solution of highly stable amine, not affected by oxygen

Absorbent has no vapour pressure

SO2 out is 25-100 ppm regardless of inlet concentration

The only waste effluents are the acids, particulates and very small acid flow from HSS removal

SO2 byproduct: a high value commodity or converted to sulfur or H2SO4

Process Flow Sheet

SO2 + H2O H+ + HSO3-

HSO3- H+ + SO3

- -

R1R2R3B R1R2R3BH+

Unique absorbent

B B X- X-

BH+ B BH+ BH+ HSO3-

Pure water saturated SO2 after regn.

Introduction

Regenerative process

Developmental studies @ IIP/EIL

Refinery applications:

A new paradigm

IIP on the frontier of acid gas treating

Solvent screening: Selection of solvent (in 1 and 2 molar solvents at 25 AND 50oc)

Absorption/regeneration data

Pure SO2

SO2-N2 mixtures

CO2-SO2-N2mixtures

Ph titrations for pka1 and pka2 estimations Regenerability tested for amount of SO2 recoverable from tested solvents Degradation studies Cost analysis Final recommendations

Steps In Solvent Selection

Liquid

outlet

Stirrer Motor

N2

SO2

CO2

Needle valve

NRV

Capillary manometer

SS/glass/Silicon tubing

Sweet Gas outlet (for analysis

Feed gas Analysis

Three way valve

Three Way

Soap bubble for flow rate

or GC

Gas inlet

Gas Phase

Liquid Phase Water

in

LABORATORY SET UP

All measurements in cm

8 10 6 6

7.2

7.2 7.2

N2

CO2

SO2

Operating variables studied:

Effect of:

pH

Temperature

Solvent concentration

0

2

4

6

8

10

0 2 4 6 8 10

SO

2 a

bso

rbed

, g

m

pH

Effect of pH on SO2 absorption

1.00

1.05

1.10

1.15

1.20

1.25

1.30

25 45 65

SO

2 a

bso

rbed

, m

ole

s/m

ole

p

iper

azi

ne

Temperature, oC

Effect of temperature on absorption

0.00

0.30

0.60

0.90

0 10 20 30

SO

2 m

ole

s/m

ole

Amine concentration, %

Effect of amine concentration on SO2

absorption

Absorption studies Effect of molecular structure of solvent

0

2

4

6

8

10

0 500

SO

2 a

bso

rbd

, gm

Time, min.

Absorption behaviour of SO2 in solvents for SO2-N2 mixture with /

without CO2

SHORTLISTING OF AMINES

Amine Abs. Reg. % Reg. Time Time

(amine) (am Slt)

AGSL 1 ~ ~

AGSL 2 ~

AGSL 3

AGSL 4 ~

AGSL 6 # ~ ## ##

AGSL 7

AGSL 8

AGSL 9 # ~ # ~

AGSL 10 # ~ # ~

AGSL 11 ~

AGSL 12 ~ x x

AGSL 13

AGSL 14

0.00

2.00

4.00

6.00

8.00

10.00

12.00

0 200 400 600 800

SO

2 A

bso

rb

d,

gm

Time, min

Absorption Behaviour of Solvent for SO2 and SO2-CO2 Mixtures of N2

SO2 CO2 - SO2

0

5000

10000

15000

20000

25000

30000

35000

40000

0

100

200

300

400

500

600

700

SO

2,

pp

m

Time, min

CO2 and SO2 analysis by GC (SO2 - CO2 - N2 mixture)

so2 co2

CO2, ppm

0

0.5

1

1.5

2

2.5

SO

2 m

ole

s/m

ole

am

ine

Amine

Abs-Regn Behaviour of 4 shortlisted solvents

SO2 absorbed

SO2 in regentd amine

SO2 recovered

SOLVENT LOADING DURING ABSORPTN. REGEN.(moles/mole)

SOLVENT START 1ST CYCLE 2ND CYCLE 3RD CYCLE 4TH CYCLE

min. max. min. max. min. max. min. max. min. max.

Solv. A 0 2 1.5 0.6 2.24 1.4 0.8 2.4 1.8 0.7 2.6 1.2 1.4

Solv. B 0 2.2 1.5 0.8 2.14 1.7 0.4 2.4 1.7 0.7 2.5 1.6 0.9

Solv. C 0 2 1.4 0.6 1.97 1.9 0.1 2.3 1.7 0.7 2.5

Solv. D 0 2.1 1.7 0.3 2.29 1.7 0.6 2.2 1.8 0.5 2.4 2 0.4

Solv. E 0 2.1 1.7 0.4 2.16 1.6 0.5 2.3

Total Data Points For Absorption - Regeneration

DATA POINTS No. OF AMINES STUDIED 12 PURE SO2

1 Molar 12 2 Molar 12

SO2-N2 MIXTURE AT 50oC 12 AT 25oC 12

CO2-SO2-N2 MIXTURE 18 CYCLICITY EXPERIMENTS 6*4

TOTAL DATA POINTS 90

◦ 200mm dia column (SS304)

◦ Thermosiphon reboiler

◦ 1.5m tall bed of structured packing

◦ 99.9% purity N2 from N2 PSA plant

◦ Pure SO2 from cylinders

◦ 10wt% solvent

•Summary

• Regenerative SO2 Removal Process Developed

• Solvent formulation identified

• VLE data for solvent generated

• Process models developed

• Processing scheme and Process conditions

identified

• HSS formation inhibitors identified

Introduction

Regenerative process

Developmental studies @ iip/eil

Refinery applications:

A new paradigm

IIP on the frontier of acid gas treating

Fuel fired in furnaces /boilers

59% FCC units

15%

Sulphur Recovery

Units 11%

Flares 5% Miscellaneous

11%

Percentage of refinery SO2 emissions

Thermal

Stage

3rd Catalytic Stage

Waste Heat Boiler

2nd Catalytic Stage

Incinerator

Sulfur Condenser

1st Catalytic Stage

Gas Cooler

SOR

System Scrubber

Regenerator

Treated Tail Gas To Stack

Air + Fuel

Rich Solvent

Lean Solvent

SO2

S

Air

Acid Gas

S S

Claus Unit with Regn. SOR System TGTU

S

vs

Thermal

Stage

3rd Catalytic Stage

Waste Heat Boiler

2nd Catalytic Stage

Incinerator

Sulfur Condenser

1st Catalytic Stage

Gas Cooler

SOR

System Scrubber

Regenerator

Treated Tail Gas To Stack

Rich Solvent

Lean Solvent

SO2

S

Air

Acid Gas

S S

Claus Unit Debottlenecking with CANSOLV System Unit

S

Air

Acid Gas

Sour Water Stripper Gas

Heater

Incinerator

1st Catalytic Stage

Waste Heat Boiler

2nd Catalytic Stage

Gas Cooler

SOR

System Scrubber

Regenerator

Treated Tail Gas

Rich Solvent

Lean Solvent

SO2

Regn. SOR System SRU

S S

To Stack

Acid Gas

Air

Sour Water Stripper Gas

FCC REACTION

II.DS.

CRUDE

UNIT

GAS PLANT

SOLVENT REGEN.

SRU CATALYTIC STAGES

FCC REGEN

COGEN UNIT

BOILER

OXIDISED SULFUR - SO2 SCRUBBING

REDUCED SULFUR - H2S SCRUBBING

SO2

TAIL GAS

SULFUR

H2S BYPASS

RICH SOR SOLVENT

RICH AMINE

H2S

SOR REGENERATOR

Reduction of significant SO2 emission

Simplifies treating SWS gas

Improves relliability and capacity of existing SRU

Expensive TGTU eliminated

Revolutionise the strategy for overall refinery sulfur abatement

Attractive alternative to cuastic scrubbing of FCCU off-gas

Regenerative

SO2 as valuable byproduct

◦ Sulphur

◦ H2SO4

No problem of land filling with solid waste disposal

Standard equipment and engineering

Low cost sensitivity of SO2 concentration

SO2 removal to <10ppm if desired

Minimum effluents

Competitive economics

Refinery infrastructure favours such process

LP steam: main energy source

Minor extension required in existing Claus plants

Regeneration unit locally separable from absorption unit

Large body of knowledge available through acid gas treatment

@ Minimum development time

Control of sulphur emission from:

Oil refining

SRUs

Cogeneration units

Power plant boilers

FCCU

Natural gas processing

Smelting

Pulp and paper

Process costs with such technology only

Weakly sensitive. High sulphur low value

fuels (Petroleum coke & visbreaker vacuum

Residue) can be burnt enomically

Introduction

Regenerative process

Developmental studies @ iip/eil

Refinery applications:

A new paradigm

IIP on the frontier of acid gas treating

Process for SO2 removal from flue gas streams

EIL-IIP-NRL

Porcess for removal of Hydrogen sulphide (H2S) from sour gas stream:

IIP-KRL ◦ A novel catalyst formulation with promotor for

enhanced regeneration ◦ Reduces H2S down to <4ppm

Process for recovery of Carbon dioxide from flue gas stream;

Min. Fertilizers

◦ Novel solvent CO2SOL-10

Innovations on use of solids with absorbents

Unit for Lab Studies Automated Unit for absorption / regeneration and kinetic studies

All glass continuous unit

Auto-titrator Metrohm Ion Exchange Chromatograph

director@iip.res.in